The proposal deals with membrane permeability and cellular compartmentation as controlling elements in the physiology of intact plant organs, in tissue slices, and in cellular organelles. Attention is focused on the cyanide insensitive, or alternate, respiratory electron transport path and its physiological role. We wish to learn more about the nature of the alternate path, the regulatory aspects of its engagement, and the feedback mechanism whereby its operation stimulates respiration and decontrols glycolysis. Ethylene, CN and low levels of CO (less than 1%) all stimulate respiration of intact fruits and tubers ostensibly by augmenting the CN-insensitive path. We plan to study the effect of other transition metal ligands. We believe that the alternate path forms superoxide and hydroxyl radical, and perhaps H2O2 and singlet oxygen. One or the other of the latter presumably attacks membrane components so that permeability is altered and positive effectors gain access to regulative enzymes. We will investigate the effect of salicyl hydroxamate, a specific inhibitor of the alternate path - and from radical traps on the respiratory burst and ripening which are evoked by ethylene, CN and CO. Whereas the respiration of many fruits and tubers is stimulated by ethylene or cyanide fresh slices therefrom are CN sensitive. We have established a firm correlation between lipid breakdown in slices and the loss of CN insensitivity. When phospholipid - and presumably membrane lipoprotein - is resynthesized, slice respiration rises, and CN-insensitivity is restored. We wish to study the structural aspects of the engagement and disengagement of the alternate path in CN-sensitive and CN-insensitive mitochondria respectively, with emphasis on the role of specific phospholipids and lipoproteins. In addition to our search for transition metal ligands which may augment the alternate path we will examine transition metal chelators, viz. copper chelators, to determine whether they inhibit the respiration of CN-insensitive mitochondrin or slices synergistically with CN.